Because more than one mealybug
species can be present in a vineyard,
the research team has investigated
the possibility of combining pheromones
to make “generic” mealybug
lures that would attract all four
species simultaneously, so that growers
would only have to put out one
trap, instead of one trap for each
species that might be present.

With some types of insects, for
example lepidopteran pests, using
mixtures of pheromones would be
risky because the pheromones can
interfere strongly with each other,
resulting in none of the target species
being attracted to a lure containing a
blend of the pheromones of each
species. However, preliminary trials
withmixtures of a couple of themealybug
pheromones have indicated that
there is minimal interference, and the
concept of generic mealybug lures for
vineyards may be practical.

If there is no interference among any
of these pheromones, then it will even
be possible to make custom mixtures of
the pheromones that contain only two
or three pheromones, for vineyards
where there are only two or three
species present. However, it will also be
necessary to check that non-target
species of mealybugs, which are not of
economic importance, are not crossattracted
to the pheromone lures, resulting
in false positives.

Commercial development
of pheromones

Currently, of these four pheromones,
only the vine mealybug
pheromone is commercially available,
but Millar is working to transfer
the manufacturing technology to
companies that produce pheromone
products.

None of the pheromones are protected
by patents, so all are freely available
for commercial development.
However, companies also need to
know that there is a substantial market
for these products, so growers should
communicate their needs to company
representatives to expedite the entry of
mealybug pheromone traps into the
marketplace.

These pheromones all share a number
of desirable characteristics for use
in pheromone trapping.

First, they are all very powerful
attractants for male mealybugs, so that
even small populations can be
detected. This can also be a disadvantage
because mealybugs have been
caught in traps located over onequarter
mile from the nearest known
infestation.

Second, field trials have shown that
the standard rubber septum type
pheromone lures remain attractive for at
least two months under field conditions,
minimizing the number of lure changes
required throughout one season.

Third, the lures require only a tiny
dose of pheromone (0.025 milligrams
or less), which will help to keep lure
manufacturing costs down

The fourth characteristic is both an advantage
and a disadvantage. That is, the chemical

structure of each pheromone
is different, so each pheromone
specifically attracts only its own
species

The advantage is that if you see
mealybug males in a trap baited with
the pheromone for species X, you
know immediately that these males
must be species X, without having to
try and identify them.

The disadvantage is that in vineyards
with more than one mealybug
species, youmight have to put out separate
traps for each species.

One further issue is that “grass”
mealybugs (Phenococcus sp. and
Chorizococcus sp.) have been caught in
pheromone traps baited with the vine
mealybug pheromone in some North
Coast vineyards. It is not yet clear
whether they were attracted to the
pheromone, or were simply present in
such high densities that they were accidentally
caught in the traps. This will
be resolved soon in further field tests.